I think a lot of it depends on how you want your book to be perceived. The line “you can’t judge a book by its cover.” is kinda false if you really want to have your work taken seriously. If this is more of a casual thing, and you just like writing for fun, then I think a really simple cover or even something you’ve drawn yourself is cool and perfectly fine.
If you want to really showcase your work and take this more seriously (in search of high read #s & subscribers), I think if you’re not an artist, commission one for a good cover. Artist need work and it’ll really make your work stand out, so its a win win.
Instagram is a really good place to find Artists. I hired mine through there, and most of them aren’t too costly, especially if its just for a cover.